Answers
Why do clear phone cases turn yellow?
Short answer: clear cases are made of TPU, and TPU oxidises under UV light, heat and skin oils. The plastic itself yellows — it isn't surface dirt, so cleaning won't undo it.
Why do clear phone cases turn yellow?
Clear cases are almost always made from thermoplastic polyurethane (TPU). TPU yellows over time because of a chemical reaction — ultraviolet light from the sun, heat from the phone, and skin oils gradually break down the polymer chains and cause them to oxidise. The plastic itself changes colour; it isn't dirt on the surface. That's why cleaning never fully restores a yellowed clear case.
How long before a clear case yellows?
It varies with how much sun and heat the case sees. A clear TPU case used mostly indoors can stay clear for 6–12 months. A case that lives in a bag by a sunny window, in a car, or on a phone that gets used heavily outdoors can start yellowing in 2–3 months. Thicker, more rigid clear cases (harder TPU or hybrid TPU/polycarbonate) usually yellow more slowly than soft, ultra-flexible ones.
Can you fix a yellowed clear case?
Not really. Some home tricks — a baking-soda paste, hydrogen peroxide soaks, denture tablets — can lighten mild discolouration temporarily, but the underlying oxidation doesn't reverse and the yellow comes back. The practical options are to replace the case every 6–12 months, choose a UV-stabilised clear case (marginally slower to yellow, still yellows), or move to a printed or coloured case where the artwork hides discolouration.
Does Miarobi sell clear cases?
No. Miarobi is a printed-case brand — every case has an illustrated design on a dual-layer TPU + polycarbonate shell, applied with UV-cured pigment ink. Because the print covers the surface, the visible yellowing problem doesn't apply the way it does to fully transparent cases. If a completely clear look is what you want, this isn't the right brand.